Influence of ultrasound and diamond burs treatments on microtensile bond strength

• Published in: Indian journal of dental research 2012-05, Vol.23 (3), p.373-377
• Main Authors: Conde, Alexandre, Mainieri, Vivian, Mota, Eduardo, Oshima, Hugo
• Format: Article
• Language: English
• Subjects: Analysis; Bond strength; Curing; Dentin; diamond bur; Diamond crystals; Diamonds; Etching; Failure; Light; microtensile bond strength; Scanning electron microscopy; Teeth; Ultrasonic imaging; ultrasound
• ISSN: 0970-9290; 1998-3603
• DOI: 10.4103/0970-9290.102232

Objective: To compare surface treatments with CVDentUS ® ultrasound tips (UT) and KGSorensen ® diamond burs (DB) on etched (e) and non-etched (n/e) dentin. The microtensile bond strength (μTBS) was measured and fractography was assessed by scanning electron microscope (SEM). Materials and Methods: Sixteen molars were divided into four groups of four teeth each according to treatment (DB-n/e; DB-e; UT-n/e; UT-e). The teeth were restored, sectioned into samples for μTBS (n=40) and tested on a EMIC DL-2000 universal machine (0.5 mm/min) and analyzed by SEM for fracture classification. Statistical Analysis: For analysis of the data on μTBS, the two-way ANOVA, using treatment and acid etching as fixed factor, and the Tukey test were used (α=0.05). To failures classification in cohesive in dentin (CD); cohesive in composite resin (CC); cohesive interfacial on base or top of hybrid layer (CBT); cohesive in adhesive (CA); mixed (M); interfacial on smear layer (S) the Fisher's exact test (α=0.05) was performed. Results: The mean values of μTBS (in MPa) in the different groups were as follows: UT-e: 45.31+-8.16; DB-e: 34.04+-9.29; UT-n/e: 15.17+-3.71; and DB-n/e: 9.86+-3.80. On analysis of the SEM micrographs, the DB-n/e group showed total obstruction of dentinal tubules; the UT-n/e group showed partial desobstruction of dentinal tubules and irregular surface; the DB-e group showed complete desobstruction of dentinal tubules; and the UT-e group showed complete desobstruction of dentinal tubules and irregular surface. Conclusion: The combination of ultrasound treatment and acid etching provides high values of μTBS. An association exists between CA/CC failures and the UT method, CBT failure and the DB method, CBT/CC failures and etching, S failure and non-etching.